It is known to provide an inflatable vehicle occupant protection device, such as an air bag, for helping to protect an occupant of a vehicle. One particular type of air bag is a frontal air bag inflatable between an occupant of a front seat of the vehicle and an instrument panel of the vehicle. Frontal air bags may be driver frontal air bags or passenger frontal air bags. When inflated, the driver and passenger frontal air bags help protect the occupant from impacts with parts of the vehicle such as the instrument panel and/or a steering wheel of the vehicle.
Frontal air bag modules may include vents for directing inflation fluid away from the air bag. The vents may be adapted to vent inflation fluid depending on sensed or otherwise determined conditions, such as vehicle conditions, occupant conditions, or both. For example, a frontal air bag vent may be adapted to vent inflation fluid in response to whether an occupant is in a normally seated position or positioned away from the normally seated position when the air bag is deployed.